\Header{panel.smooth}{Simple Panel Plot}
\keyword{hplot}{panel.smooth}
\keyword{dplot}{panel.smooth}
\begin{Description}\relax
An example of a simple useful \code{panel} function to be used as
argument in e.g., \code{\Link{coplot}} or \code{\Link{pairs}}.\end{Description}
\begin{Usage}
\begin{verbatim}
panel.smooth(x, y, col = par("col"), bg = NA, pch = par("pch"), cex = 1,
             col.smooth = "red", span = 2/3, iter=3, ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x,y}] numeric vectors of the same length
\item[\code{col,bg,pch,cex}] numeric or character codes for the color(s),
point type and size of \code{\Link{points}}; see also
\code{\Link{par}}.
\item[\code{col.smooth}] color to be used by \code{lines} for drawing the
smooths.
\item[\code{span}] smoothing parameter \code{f} for \code{\Link{lowess}}, see
there.
\item[\code{iter}] number of robustness iterations for \code{\Link{lowess}}.
\item[\code{...}] further arguments to \code{\Link{lines}}.
\end{ldescription}
\end{Arguments}
\begin{SeeAlso}\relax
\code{\Link{coplot}} and \code{\Link{pairs}} where \code{panel.smooth}
is typically used;
\code{\Link{lowess}}.\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
data(swiss)
pairs(swiss, panel = panel.smooth, pch = ".")# emphasize the smooths
pairs(swiss, panel = panel.smooth, lwd = 2, cex= 1.5, col="blue")# hmm...
\end{ExampleCode}
\end{Examples}

